Texturing a sphere with a tiled texture
Your texture is  not tileable, that's why it doesn't scale well: to make it tileable you can import it in Photoshop or Gimp, apply the "offset" filter at half the resolution of both X and Y dimension (1120 x 787 in your case), and use the stamp and/or the healing tool to eliminate the seams crossing. Pay attention not to touch the border of the image, or you will have to redo the operation.
When the texture is seamless you can generate the relative normal map (i.e. with the Nvidia free plugin for Photoshop, or free online sites), or use a black/white version to control a "bump" node.

In addition I suggest you, instead of fixing the ratio between Diffuse and Glossy (0.1) to plug a "Layer Weight" node (Fresnel output) and control the amount of glossiness with his control: this adds some Fresnel effect, more glossiness at the outer border of the sphere (relatively to the point of view), which helps beliavability of every material.